Submission #421491

#	Time	Username	Problem	Language	Result	Execution time	Memory
421491		schse	Ancient Books (IOI17_books)	C++17	50 / 100	202 ms	27532 KiB

books

#include "books.h"
#ifndef EVAL
#include "grader.cpp"
#endif
#include <bits/stdc++.h>
using namespace std;

long long minimum_walk(std::vector<int> p, int s)
{

	vector<int> cycle(p.size(), -1);
	vector<vector<int>> cycles;
	vector<pair<int, int>> cmmc;
	long long triplenght = 0;

	for (int i = 0; i < p.size(); i++)
	{
		if (cycle[i] == -1 && p[i] != i)
		{
			int t = i;
			cycles.push_back({});
			cmmc.push_back({INT32_MAX, INT32_MIN});
			do
			{
				cmmc[cmmc.size() - 1].first = min(cmmc[cmmc.size() - 1].first, t);
				cmmc[cmmc.size() - 1].second = max(cmmc[cmmc.size() - 1].second, t);
				cycles[cycles.size() - 1].push_back(t);
				cycle[t] = cycles.size();
				triplenght += abs(t - p[t]);
				t = p[t];
			} while (t != i);
		}
	}
	if (cmmc.size() == 0)
		return 0;

	int t = 0;
	while (cycle[max(s - t, 0)] == -1 && cycle[min(s + t, (int)cycle.size() - 1)] == -1)
		t++;
	triplenght += 2 * t;
	/*
	for (auto i : cmmc)
	{
		if (i.first <= s && s <= i.second)
		{
			triplenght += 2 * t;
			break;
		}
	}
*/
	// triplenght += 2 * cmmc[0].first; //initial walk

	int mx = cmmc[0].second;
	for (int i = 1; i < cmmc.size(); i++)
	{
		if (mx < cmmc[i].first)
			triplenght += abs(cmmc[i].first - mx) * 2;
		mx = max(mx, cmmc[i].second);
	}
	//if (s < cmmc[0].first || s > mx)
	//	triplenght += 2 * t;

	return triplenght;
}

Compilation message (stderr)

books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:16:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |  for (int i = 0; i < p.size(); i++)
      |                  ~~^~~~~~~~~~
books.cpp:54:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |  for (int i = 1; i < cmmc.size(); i++)
      |                  ~~^~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30